JPS583020B2 - High-speed bright annealing equipment for metal wire - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present inventor has submitted a ``High-frequency induction heating method for metal wire'' (Japanese Patent Application No. 18513/1983), which is particularly applicable to high-frequency induction heating of metal wire fed out from a wire drawing device and running at high speed. Although a method suitable for heating has been provided, the present invention relates to a high-speed bright annealing (tempering) apparatus for metal wires that uses a cooling method in a bright heat treatment gas atmosphere in addition to this heating method, and will be described in detail below. .

Metal wire is drawn several times before it is turned into a product from an ingot, and at least part of the structure of the metal wire changes each time it is drawn. It is well known that heat treatment is required to increase stickiness.

However, if this heat treatment is performed in air, the surface will oxidize and the performance will deteriorate, so it is desirable to perform bright heat treatment to prevent oxidation during the heat treatment process and maintain the original shiny state.

For this reason, bright annealing has conventionally been carried out by installing a metal tube in a heat treatment furnace, creating a constant gas atmosphere inside the metal tube, and passing a metal wire through the tube. The limit is 20 to 30 m/min.

On the other hand, the processing speed of metal wire drawing equipment is, for example, 400 m.
Since the speed is as high as /min, there is a drawback that continuous processing of wire drawing and bright annealing cannot be performed.

Also, to show an example of the wire drawing process, the generatrix (5.5 mmφ)
→(1 line, 400m/min) →2.2mmφ→A
→(10 lines, 400m/min) →1.0mmφ→
A → (several 10 lines, 400m/min) → 0.5mm
It looks like φ→A→product (A represents bright annealing treatment),
Because bright annealing is performed every time wire is drawn, it is customary for the wire to go back and forth between the bright annealing furnace and the wire drawing device for three days or more after the wire is inserted into the wire drawing device before it becomes a product.

Therefore, there is a need to improve the efficiency of bright annealing.

The present invention eliminates the above-mentioned drawbacks. FIG. 1 is a schematic diagram of the configuration of an embodiment of the present invention, and FIG. 2 is a detailed structural diagram of the heating section in FIG. 1.

The metal wire 1 sent from a wire drawing device etc. is inserted into the wire introduction port 7.
The material is then led to a bright annealing apparatus (furnace) 3 having a bright heat treatment gas atmosphere configured as shown in FIG. 1, and first heated to a predetermined temperature in a heating section 2.

The detailed structure of the heating section is shown in Fig. 2, and consists of a shorting roll 4 made of a good conductor and a guide roll 5 made of a nonconductor, each supported by a rotatable shaft and arranged at appropriate intervals. A metal wire 1, which is a wire to be applied, is looped one or more times between them.

Further, the portions of the metal wire 1 that are applied to the short-circuiting roll 4 are in a state of passing each other, and one or more closed circuits are formed by the metal wire 1 via the short-circuiting roll 4.

If high-frequency power is supplied from a high-frequency power supply 12 to a high-frequency induction heating coil 11 provided close to these closed circuits, and a current iC is caused to flow in the direction of the arrow, for example, a sufficiently large induced current iM will flow. The metal wire 1 is sufficiently heated by the Joule heat generated by this current.

The metal wire 1 runs like a general wire in the direction of As such, it is easy to adjust the current iC, the distance between the rolls 4 and 5, the number of times of winding around the rolls, etc., and the input and output speeds of the metal wire 1 in the heating section 2 can be kept the same and equal to the wire drawing speed. .

Note that this heating section can be constructed by short-circuiting a certain length of passing metal wire or both ends of each certain length with a good electrical conductor to create one or more parallel loop circuits, and closely coupling these with the high-frequency heating coil. The structure of the short-circuiting device is not limited to that shown in FIG. 2, and various shapes can be used.

The heated metal wire 1 is then wound in the same furnace 3 around two drums 6 of a cooling section located side by side with the heating section.
While passing between two drums 6, it is cooled to, for example, about 200° C. or lower.

This drum 6 may be a cooling drum in which a cooling fluid such as cooling water is circulated, or it may be a mere guide drum and an inert gas may be forcibly blown into it. The metal wire 1 wound around these is rapidly cooled using the above method or a combination of both methods.

A bright line processing gas is introduced into the bright annealing furnace 3 through a gas inlet 9 to create an atmosphere filled with this gas, and 10 is a gas outlet.

The gas used varies depending on the material of the metal wire 1. For example, gases such as argon, hydrogen (H2), and ammonia (NH3) are used, but when using pyrolysis gas such as H2 or NH3, the open port of the furnace 3 is used. It is necessary to provide gas curtains or the like at 7 and 8 to prevent oxygen (O2) from entering the furnace 3.

Further, although the configuration shown in FIG. 1 is mainly suitable for stainless steel wire, it is also possible to bright annealing other special metal wires by selecting a cooling method suitable for the material.

As is clear from the above description, the bright annealing apparatus of the present invention (
Because the processing speed of the furnace (furnace) is fast, it is possible to make its input and output speeds equal to the delivery speed of the wire drawing device, and it can also be incorporated into the wire drawing device, which not only greatly reduces the area occupied by the device. The practical effects are remarkable, as the operating cost is halved compared to the conventional method due to the reduction in the time required for heat treatment.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of the configuration of one embodiment of the present invention, and Fig. 2 is a schematic diagram of the configuration of an embodiment of the present invention.
It is a detailed structural diagram of the heating part in the figure.

Claims (1)

[Claims] 1. A heating section that heats the metal wire to be heat treated to a predetermined temperature for a predetermined time, which is continuously fed into the furnace in a gas atmosphere for bright heat treatment, and a heating section that cools the heated metal wire to a predetermined temperature and then A cooling section that continuously sends out air is provided, and the heating section includes a short-circuiting member that electrically short-circuits the metal wire by a certain length or every plurality of certain lengths to form one or more closed circuits. A high-frequency induction heating coil that is tightly connected to a closed circuit and supplied with high-frequency current, and a metal wire sent from the heating section to the cooling section is wound around the drum and circulated inside or outside the drum. 1. A high-speed bright annealing apparatus for metal wire, characterized in that cooling drums are respectively provided to maintain the running speed of the metal wire entering and exiting the furnace at the same speed.